How long can freshly expressed breastmilk stay outside before storing in chiller given our weather in Singapore?

Normally I will only let it sit for a maximum of 1-2 hours outside and about 3 hours in aircon before putting into the freezer. It will be safer to chill it immediately unless baby is waking up in 1-2 hours for the feed. The weather is really hot right now so it is difficult to gauge exactly how long the milk can stay out.